There are many applications calling for a pumping system which automatically senses the presence of liquid and pumps the liquid from one location to another. Sites containing contaminated ground water, for example, frequently require simple reliable pumps which can fit down a small diameter well. These pumps must be able to withstand corrosive fluids, and are preferably operated pneumatically to avoid the possibility of explosions caused by electrical sparks contacting flammable fluids in the well.
In practice, these pumps are typically suspended vertically within a sump or well, and the compressed air is applied through a valve to the pump's chamber via an appropriate conduit coupled to an air inlet port. Each cycle of the pump's operation comprises an intake phase and an evacuation phase. During the intake phase, liquid within the well enters the pump's chamber through a one-way check valve at the bottom of the pump's housing, displacing the air inside the pump's chamber. The displaced air escapes through an air exhaust conduit as the fluid filled the pump chamber. During the pump's evacuation phase, compressed air is directed into the pump's chamber to force the liquid out via a liquid outlet port.
One such pump is disclosed in my U.S. Pat. No. 5,004,405 issued Apr. 2, 1991, the contents of which are hereby incorporated by reference. The pump continuously fills and empties itself by means of a float which senses the level of liquid in the pump's chamber. After a sufficient quantity of liquid has entered the chamber, the rising float activates a control valve to allow compressed air into the pump's housing, displacing and discharging the accumulated liquid via the discharge port. As the pump falls with the falling liquid level, it activates the control valve once again to stop the flow of compressed air while opening an air-exhaust port and vent the pump's chamber, permitting more liquid to enter. The pump continues to operate automatically so long as there is sufficient liquid to trip the switch and there is compressed air of sufficient pressure to overcome the head against the pump which is pushing the liquid.
Naturally, compressed gases other than air can be used in these pumps, and it should be understood that the convenient use of the term "compressed air" throughout the specification and claims is meant to include all suitable compressed gases.
One object of the present invention is to provide a pump configuration which can be sent down a smaller diameter bore hole of an oil well, and use less energy, than pumps currently in use in the oil industry. Currently, the oil industry uses a "tip up" pump with sucker rods and a 50 hp motor. These pumps have a grasshopper-like appearance, and are frequently seen dipping up and down in some oil fields in California and elsewhere.
Another object of the invention is to provide a pump which can be easily moved to, installed and serviced at, and removed from a well site.
Another object of the invention is to provide a valve mechanism which switches the pump between its intake and discharge phases which resists swelling [, swelling] and clogging when the pumped liquid is corrosive or contains debris.